This will help the government achieve its local content programme objectives, the company’s top management argues.

“Eunisell brings in its own assets and resources to help achieve early cash flow and accelerate the marginal oil field development”, says Chika Ikenga, Eunisell’s Group Managing Director. “Our track record speaks for itself. We are there to help build viable, Nigerian oil and gas businesses,” he explains.

“Achieving the objectives of the local content programme, is a vital factor in sustaining Nigeria’s economic development and oil industry growth.

“The marginal field development programme and the recent divestments of fields by IOCs have increased the participation of Nigerians in the oil and gas industry. The gap in technical and financial resources that have fallen out of recent developments, is being closed by Eunisell’s unique production solutions”.

Ikenga notes that the company’s taking the Qua Ibo field to first oil “is a clear example of what we have done.

“Apart from building a production facility in record time with the skills of highly experienced Nigerian professionals, Eunisell’s fast track solution helped to get these fields into early cash flow”.

Eunisell’s fast track production facilities also helped to achieve first oil in record time at Oil Mining Lease (OML) 56 in Delta State, and the OML 46 Atala field in Bayelsa.

“Many wells today where you have well integrity and zonal isolation issues are a result of a failure of the cement”

It is practically impossible to discuss well completions without a nod to the cementing process: the standard procedure that isolates the various down-hole formation zones.

Prior to 1921, one of the greatest obstacles to successful development of oil bearing sands was the encountering of liquid mud, water and other sediments during and after the process of drilling a well; this was before the art of well cementing was “perfected.” It is easy to assume that almost a century later in 2019, well cementing would have advanced so much technologically that no undesirable basic, sediment and water (BS&W) would be produced from oil wells due to the failure of the cement to seal. Unfortunately, we still have frequent challenges mainly due to the hole geometry, formation types, pore pressure, differential pressure, etc. The production from typical oil wells which are hampered by BS&W intrusion require time, energy and expense to correct and has led to the abandonment of many wells which would otherwise have developed more profitable results for operators.

WAI Deployed in a Deepwater well

In July 2019, the French major Total announced that it successfully deployed a new breed of cementless completion called the Welltec Annular Isolation (WAI) in the Moho North Albian field. According to Ronan Bouget, the Drilling and Completions manager of Total E&P Congo, the technology was jointly developed with Welltec. Gbenga Onadeko, Senior Vice President, Welltec Africa, tells Africa Oil+Gas Report that the “Welltec Annular Barrier (WAB) provides effective zonal isolation at discrete points within the well, whereas, the WAI provides zonal isolation across the length of the reservoir replacing the cement.”

“Many wells today where you have well integrity and zonal isolation issues are because of failures of cement. Attempting to place cement and achieve full circumferential coverage around a piece of pipe that is over three kilometres downhole in a well could be challenging due to gravitational effects especially if the well has some deviation, Gbenga explains. “The cement will tend to go to the lower side of the liner / casing while the upper side of the liner / casing may be left without cement, creating what is called a channel. The cement could also be contaminated due to interactions with mud and formation cuttings. The channels and micro annulus may lead to a loss of integrity or isolation between zones which could accelerate the production of water or gas break through.”

Squeeze cementing is a remedial cementing technique deployed when challenges occur during the primary cementing process. Gbenga continues. However, “this has a relatively low success rate with high cost. This is often the reason why wells produce 60% to 70% water cut from day one and is a contributor to cost overrun. In addition, depending on the age of the well, for example in the case of a relatively old well, cracks could develop in the cement due to thermal expansion and contraction, which can then lead to the leakage of gas or water.”.

Major IOC Review of 96 Cement Operations

The WAI technology can be deployed in various and even hostile well environments, adds Joseph Bagal, who is the Director of Well Completions for Welltec Africa. Joseph is a sand control expert with global experience and gained significant knowledge of the Niger Delta from various assignments living and working in Nigeria. He is familiar with the challenges associated with clastic depositional environments of the Niger Delta and he says that “although the first deployment of the WAI was in the Moho North which is a carbonate field, the WAB and the WAI technologies are also applicable in clastic environments.

WAB Preventing Water and Gas Production in the Benin Basin, Offshore, Nigeria

The materials used to manufacture the WAI are the same as used for very hostile environments including within Geothermal wells. They are highly resistant to corrosion and specifically selected for their life of well properties. Today, the industry continues to use cement because that is historically the solution utilized (even though as mentioned many well integrity issues arise from cement failure). The technical qualification performed on the Welltec Annular Sealing Products (WAB, WLP, WAI) are more stringent than the qualification tests on cement, when used for isolation – particularly their sealing capabilities” he claims.

The application of the WAI on the Moho North field dates back to 2016, when TOTAL E & P Congo selected the WAB in the development of the Moho North Albian field “this initial application was in conjunction with cement (assurance to provide a seal to isolate the zones)”, comments Joseph. “Total initially selected a cemented and perforated liner solution, the liner length was short and deep, implying the volume of cement was relatively small, which increases the operational risk of cementing the reservoir section. Because of the potential of cement contamination and also to increase the success rate of placing it behind the liner, the volume of cement pumped was increased by enlarging the hole (under-reaming) and drilling deeper i.e. a longer rat hole section, which placed the toe of the well within less preferential sections of the formation increasing the drilling and production risks.

With the liner deployed and cement in place, the WAB is expanded quickly under full surface control sealing against the formation rock, displacing the cement, providing a high integrity pressure isolation between zones. This in turn ensures that even if channels or micro-annulus are present in the cemented interval, effective isolation is still achieved within the annulus.

WAB for Cement Assurance in a Deepwater well

Following this initial success with the WAB and the efficiency drive by TOTAL E & P Congo to further reduce drilling expenditure (partially driven by the low commodity prices), this presented an opportunity to extend the scope of the utilization of the WAB to make the project more economical. This provided the impetus for the joint development of the WAI between Welltec and Total E & P Congo.

The WAI technology is based on the WAB platform, with the packers extending over the complete length of the liner (the joints are not covered). The WAI effectively replaced the cement within the annulus across the reservoir interval. A large quantity of Welltec Proprietary seals are installed along the length of the WAI, providing zonal isolation down to each 20 cm, with each seal qualified for 4,500 PSI of differential pressure. By eliminating the cement completely from the reservoir section of the wells, the drilled interval is shortened (i.e. no rat hole), the need to under-ream for hole enlargement is removed along with the need to perform extensive wellbore cleanout. This reduction in work scope delivered significant savings in the number of days predicted to complete the well compared to the best composite result achieved in the field. Non-Productive Time (NPT) from the wells where the WAI were deployed was reduced. The use of the WAI led to a reduction in rig time and saved a huge amount of cost for our client.”

Returning to the WAB technology, which has been deployed all over the world including clastic environments in the North Sea and as well as in the Benin Basin Offshore Lagos, Nigeria. “If you have a clastic reservoir, cement is pumped all the way to the cap rock to achieve isolation and well integrity. We successfully used the WAB product to assist a minor deepwater operator in Nigeria to achieve approximately 3,000 barrels per day of oil production. Two WABs were installed in the side-tracked section of their last well which successfully eliminated the water cut, but more importantly eliminated the gas flowing from the gas gap and the associated sustained casing pressure as monitored at the well head. It is understood that the well has kept this state since 2017 when it was put on production.”

The catch with the oil and gas industry however, is the conservative nature of the industry in adopting new and improved technology. As an innovative company with pioneering technologies, Welltec often experiences this challenge. Gbenga sums it up with these words: “We develop cutting edge technologies and work extremely hard to convince our clients to deploy the value adding solutions. One of values we add to the industry is to assist our clients in overcoming their initial reluctance. We want to ensure that these technologies are included in their field development plans to avoid paying premiums later due to rush mobilizations. Including the technologies in their initial plans reduces the risk of budget variation. With the WAI, we predict that cost savings of up to $75Million to $100Million over a 15 to 20 wells deepwater field development plan can be achieved (including reduced NPT). Proportional savings can also be achieved in onshore and shallow offshore markets. Approaching it from a larger scale makes the value proposition more obvious. We like to think that we work on solutions that are best for the well and the overall project. In most cases, our industry is integral to the economies of the oil and gas producing countries. We therefore believe that we are having a positive impact on the overall wealth of the nations we operate in.”

It is statistically insignificant to sequentially feed the flow from each oil wellhead once a month, to a central test separator so as to evaluate the well production performance and determine the flowrate of each phase (oil, gas and water) after separation; it is unrepresentative and inaccurate. Wells seldom flow at constant rates and the ‘one-day’ test separator rate is a random sample of one, out of thirty possible rates. This is statistically insignificant.

Neftemer™ is a non-intrusive clamp-on Multiphase Meter that measures unseparated crude oil flow in well flowlines and oil-flow pipelines. It provides measurement of oil, produced water and associated gas in the following units: liquid mass flow, tons/day; gas volumetric flow, m3/day and water cut, mass fraction. Preferably, Neftemer is installed on a vertical section of pipeline with flow upward. When in operation, its parts do not come in contact with the product fluids, do not change its direction, do not produce extra hydraulic resistance, nor does it influence the hydrodynamic characteristics of the flow or the physical and chemical properties of the product fluids. The measurements are taken without conditioning the flow (i.e. without homogenization or separation).

This clearly eliminates the persistent issues associated with back allocation for obvious fiscal reasons. The oil rate is accurately measured directly at the wellhead; the gas flow is not diverted to the flare where bulk of the gas may or may not be measured but the Neftemer measures this volume upstream of the well; also, it accurately captures the water flow rate.

At the separator where BSW is determined, back allocation of gas volume and water rate remain problematic. Moreover, in practice, total Flow-Station rates (fluid flow), are seldom used even when the oil rate injected into a bulk export line is accurately metered e.g. via an available LACT unit. Rather, each contributory flow station is assigned a volume based on a so-called reconciliation factor, determination of which is opaque in most cases.

This practice simply does not make room for a representative and accurate determination of oil, gas and water rates simultaneously; a task required for optimal tuning of the well, and effective reservoir management practices.

How does the Neftemer Multiphase Meter achieve all this seamlessly? The secret is in its construction. It comprises of a gamma-ray attenuation transducer which is located near the wellhead in a hazardous area with secondary equipment comprising a data processing unit located in a safe area in a control or equipment room. A user display (personal computer) and printer may be used for setting this up. The gamma-ray attenuation meter comprises a gamma radiation source mounted in a source housing and a flameproof gamma radiation detector all mounted on a special mounting bracket. The density and composition of the unseparated well fluids as well as gas flow velocities, are determined from the attenuation of gamma radiation.

As a clamp-on device, it can be mounted without cutting the flow line; upstream of the pipeline. The length of straight pipe both upstream and downstream of the gamma ray beam should be not less than 0.5m. It also has other plush parameters including two communication links (see Fig. 1). The DCS link is used to provide measurement results to the customer. Output data will be: oil, water and gas flow rates, water cut, average density of flow. The auxiliary link is intended for downloading data archives by a service engineer.

Finally, production engineers need to know if the well is operating within its performance envelope or not and tune it appropriately. Reservoir engineers need accurate oil, gas and water rates to carry out meaningful material balance calculations and determine total underground withdrawal for each reservoir; run realistic reservoir simulation models and generate meaningful medium and long term production forecasts for the business. Current operations practice and use of ‘one-day’ test separator rates simply do not allow for these essential and critical calculations to be accurately carried out. This practice also leads to endless disputations between the field operator and regulators over what volumes royalty calculations should be based upon. With Neftemer™, however, impactful reservoir management and peace of mind is assured.

30-day production rates surge by 78%
Schlumberger has reported that its technologies helped dramatically increase production and operational efficiencies of Eagle Ford and Permian Basins, which are geologic sequences with extensive shale rock reservoirs in North America.
“In US Land, Well Services BroadBand* unconventional reservoir completion services have been deployed in 14% more wells and in 52% more stages as compared to 2014”, the company declares in a company report.
“BroadBand technology maximizes wellbore coverage and reservoir contact to increase production and recovery by stimulating and propping open every fracture from tip to wellbore. The Eagle Ford and Permian Basins reflected the highest activity in 2015 while total activity covered six basins and 32 operators”, the company disclosed.

The Nigerian oilfield service company Ofserv says it has added Well Production Monitoring to its suite of services. It is deploying this solution in partnership with Wireless Measurement, a UK based oilfield solutions provider.

The service “offers a comprehensive real time system delivering monitoring and alarm data from remote oilfield equipment including wellheads and pipelines”, Ofserv declares in a widely distributed newsletter. “Our configurable data and control systems seamlessly link the wellhead or pipeline to operators, engineers, managers and stakeholders”, the company says.

Ofserv will showcase the overall delivery at its booth at the Nigerian Annual International Conference and Exhibition of the Society of Petroleum Engineers (SPE), holding in Lagos, from August 2 to 4, 2016. The SPE NAICE is the largest gathering of petroleum engineers on the continent.

“There is no need to install wired or conventionally powered infrastructure on site for this service to work”, Ofserv explains in the statement. “Our autonomously powered wireless system provides a perfect ‘well head to office’ retrofit solution for existing unmonitored operations. With simple to install proven products, easy to use software and first class support, we offer a complete package to provide remote oilfield services. Ofserv adds that its wireless comprehensive digital oilfield solution include:

Seismic Equipment Manufacturer, Sercel has launched QuietSea™, its new passive acoustic monitoring (PAM) system designed to detect the presence of marine mammals during seismic operations. “Totally different from other commercially available PAM systems, QuietSea is set to revolutionize PAM within the seismic industry”, the company says in a release.